Neoplastic Transformation Induced by Heavy Ions: Studies on Transformation Efficiencies and Molecular Mechanisms.

Numerical estimates of the risk of cancer, caused by the exposure to ionizing radiations, are a topic of considerable current interest, especially in the view of the revision of the atomic bomb dosimetry and the ensuing reanalysis of the epidemiological data for the survivors of the atomic bomb explosions. As far as sparsely ionizing radiations are concerned, the epidemiological data are a good basis for risk estimation. For densely ionizing radiations, however, the linkage to epidemiological data had to be abandoned, when the new dosimetry for the atomic bomb survivors showed that the contribution of neutrons is minimal or, at least, uncertain. The carcinogenic potential of fast neutrons is, however, of importance in some areas of radiation protection. High flying aircraft and manned space activities, especially in the context of a long duration deep space flight, such as manned mission to Mars, cause critical questions with regard to the risks due to densely ionizing radiation